Yarn package



1957 A. R. PILLAR ETAL 3,334,842

YARN PACKAGE Filed Oct. 6, 1965 2 SheetsSheet 1 z M M I A Horney United States Patent 3,334,842 YARN PACKAGE Anthony Roland Pillar, Gilwern, and James William Sharpe, Pontypool, England, assignors to British Nylon Spinners Limited, Pontypool, England, a corporation of Great Britain Filed Oct. 6, 1965, Ser. No. 493,434 Claims priority, application Great Britain, Oct. 23, 1964, 43,431/64 3 Claims. (Cl. 242-177) The invention concerns improvements in or relating to yarn packages.

In this specification, the expression yarn package denotes a tube, bobbin or other like former upon which yarn is wound in an ordered mass, known as a build. Cone angle denotes the angle between the axis and the inclined side of the cone, that is one-half the angle at the vertex of the cone.

As is well known, yarn packages are wound both for use during the various processes of yarn preparation and as the supply for the subsequent processes of'fabric or garment manufacture.

-Over the years of nylon production, for instance, the yarn has been wound on a variety of cylindrical formers during the course of its preparation, finally ending up, say, on a conical reinforced paper tube to be used as the supply of a circular or full-fashioned knitting machine.

Owing to greater precision in regard to the various process variables both in yarn production and in knitting, and owing to improvement in the surface characteristics of the cylindrical metal tubes employed, it has been possible for some years now to employ the so-called drawtwist package of nylon yarn directly as the supply for knitting nylon stockings.

' A drawtwist package is one wound with a more or less cylindrical body and tapered ends by a ring-spindle apparatus, which apparatus is part of a machine used for drawing undrawn yarn and for imparting a low twist to the drawn yarn at wind-up. The yarn has been wound-up heretofore on cylindrical aluminum tubes or on cylindrical plastic sleeves mounted on steel cores.

Double-taper drawtwist packages to be used directly as the supply for knitting must have good take-oil characteristics so as not to prejudice the uniformity, and indeed the continuity, of knitting therefrom..To this end, the nature of the package build and of the surface of the tube or sleeve are matters which have received detailed attention, to try and ensure uniformity of take-off tension throughout the period of unwinding.

Should the take-off tension fluctuate sharply during Withdrawal from a package, say on account of the intermittent dragging of the yarn across a portion of the lower tapered end-portion of the build, it is quite possible for the yarn to break and this will lead to a so-called press off of the fabric from the needles of the'knitting machine. Even if the take-off tension is only variable over longer periods of the entire withdrawal period, inasmuch as a number of stockings will be knitted from the one package, it is likely that the length of these stockings will equally be variable owing to the different stitch sizes knitted at the different tensions.

The ideal drawtwist package for direct knitting, there- I tore, is one for which the take-off tension is low and uniform throughout the period of unwinding; and package builds which have proved more or less useful in arriving at this goal are the so-called pirn build in which the yarn is laid on to the tube with a constant traverse starting at the lower end of the build and being shifted gradually upwardly during the winding, the so-called composite pi-rn buil in which the lower tapered portion only of the build is formed from a gradual upward displacement 3,334,842 Patented Aug. 8, 1967 F ice of the successive positions of the lower reversal point of the traverse throughout the winding and the upper tapered portion is formed by cyclical variations of the successive position of the upper reversal point, and the so-called lon-g-to-short build, or decreasing traverse build, in which the yarn is laid on to the tube with a traverse stroke which gradually decreases in length throughout the winding. v

All of the above-mentioned builds avoid the pitfall of intermittent withdrawal of the yarn from around portions of the build of greater radius than that of the point of withdrawal; but none of them are blameless in regard to the introduction of variability in the take-off tension. Thus, the pirn build introduces such variability on account of the increasing line of contact of the yarn with the surface of the tube during unwinding, and on account of the tendency of coils to jam on the top taper during withdrawal; the composite pirn build introduces variability owing to the cyclical nature of the build in the upper tapered end portion: and the long-to-short buil introduces variability owing to a tendency for the take-01f tension to increase during withdrawal from the layers of longest traverse-stroke immediately prior to run-out, particularly from drawtwist packages having a long tube length, say in excess of 12 inches.

Apart from the oven-riding requirement for good take off characteristics, a drawtwist package for direct knitting is required to contain the greatest length of yarn that can be accommodated on the particular length of tube and that can be wound with a machine of the relevant dimensions in question. The yarn must be wound in a build that is stable and not, for instance, liable to the defect of sloughing. The above two additional requirements tend to act in opposition, particularly in regard to the steepness of the taper angle that can be tolerated.

One expedient that is already known and practised, which not only enhances stability but also has some beneficial effect on the uniformity of stockings knitted from the yarn, is the practice of tilting the ring of the ringtwister a few degrees so that the yarn is laid on in a wavelike motion around the circumference, which is a matter of particular importance in regard to the stability of the lower tapered end portion.

As already indicated, the surface of the tube itself is of some importance in regard to the uniformity of take-off of the layer or layers of yarn adjacent to the tube. An aluminium tube is normally employed for stocking yarn, inasmuch as that yarn must be wound up containing a considerable residual shrinkage for development after the stocking knitting operation and that the contractive force of such yarn on the bobbins necessitates an incompresso-called orange peel eflect.

It will be seen, therefore, that the requirements for a drawtwist package for direct knitting are very demanding;

and the packages which have been employed for this use heretofore have, despite the steps taken as indicated above, fallen short of what is desirable either in respect of the take-off characteristics, or of the weight of yarn wound with stability of build, or both. 7

We have now found that altogether suprising improvements in regard to the knitting performance of nylon drawtwist yarn for stockings are obtained when a long-toshort (decreasing traverse) build is wound on a frustoconical tube having a small cone angle.

Heretofore, drawtwist tubes have almost invariably been cylindrical; and the small departure from this shape that is involved in the present invention has a most pronounced effect on the knitting performance of the yarn, which effect could not have been predicted by any analogy with known conical-shaped packages, such as the well-known cone, where the helix angle of the coils is so very much larger.

Although we do not wish to be held to any specific explanation for this marked improvement in processability, we believe it is due to the reduction of tension in the yarn during unwinding from the package, particularly at the final stage thereof, and particularly when the tube is longer than the normal length for the machine.

A cone angle within the limited range of from about 1 to about 2 provides the beneficial results, whilst allowing for compatibility with present-day ring spindle apparatus of the draw-twister variety.

The use of the long-to-short build ensures not only that take-off shall be smoother, but also that a larger weight of yarn can be wound, compared with other builds, as for instance, the composite pirn build. This latter advantage results in part at least, from the stability with which the tapered end portions can be wound with relatively large taper angles particularly if, as will usually be the case, the package is built with overlapping adjacent coils, such as are produced by the practice of tilting the ring of the ringtwister, say by 3 or by 6, as already explained above. Further, the greatest taper angle is attainable when the surfaces of the tapered end portions are frusto-conical; and, therefore, the cams controlling the position of successive reversal points of the traverse will normally be of such shape as to produce these straight conical surfaces. In fact, for such purpose, the graphical projection against a number or time scale of the successive positions of the reversal points produces those points falling on a slightly curved, rather than straight, line.

The improved tension uniformity of the withdrawn yarn according to the invention also results from the only gradually varying length of surface of yarn from which the withdraw yarn is taken, compared with the more greatly varying length of surface of the composite pirn build. In contradistinction to the pirn build, there is no great length of tube with which the yarn can make contact, up to the final moment of run-out.

Furthermore, the attainment of the greatest distance between reversal points at the completion of unwinding is of value in reducing the frequency of occurrence of socalled tension rings in hose knitted from the yarn.

The invention in its broadest aspect, therefore, comprises a drawtwist yarn package for use directly in knitting consisting of continuous filament yarn wound on a frustoconical former of small cone angle in a double taper build, successively-wound layers of which decrease in length gradually from inside to outside of the build.

By small cone angle is meant an angle between about 1 and a figure, probably not exceeding 3, at which the frusto-conical former ceases to be compatible with the twisting apparatus by which the drawtwist yarn package is wound. Compatibility is dependent on the bottom .diameter being such as can be accommodated on the spindle whorl, and on the top diameter being large enough to maintain the balloon tensions above the level at which the balloon would collapse.

In the preferred form of such package the frusto-conical former is made of aluminium having an orangepeel type of surface resulting from a wire-brushing treatment, owing to the desirably low take-01f tension and the ease of fabrication compared with any known plastics sleeve for use on a metal core, and the lay of the yarn in the individual layers of the build is such that adjacent coils overlap one another at one or more points around their circumference.

Further, in presently preferred packages made according to the invention, the mean helix angles of the coils in any given layer of the build are sensibly equal, but no substantial number of adjacent coils correspond exactly as to the loci of their paths at any radius of the build. The ,former condition results from the employment .of a

constant velocity traverse motion, produced by, say, hydraulic builder means; and the latter condition results from means adopted to prevent ring tilt patterning, which defect otherwise occurs at certain radii of the build Where there is correspondence between the loci of the paths of a number of adjacent coils, such means being either the periodic variation of the spindle speed by a small amount about the mean, unharmonically with the traverse period, or the rapid and more drastic variation of the speed at the times when winding is taking place at the suspect radii of the build.

As already explained, it is further preferred to have the tapered end-portions frusto-conical in shape, so as to accommodate the maximum amount of yarn in the package.

One continuous filament yarn with which this invention is specifically concerned is 15 denier monofi-lament yarn of poly-hexamethylene adipamide. Such a yarn may be contained in a drawtwist package of which the yarn content weighs 42 oz., and the length of the conical wirebrushed aluminium tube is 14 /2 inches, the cone angle being 2, base diameter 2.66 in. and nose diameter 1.65 in. Such a package is preferably Wound with spindle speed varying at a pre-set, non-integral number of times per traverse (e.g. 3.88) and a ring tilt of 6, on a Rieter hydraulic drawtwister, the latter type of drawtwister having advantages of package build accuracy and of engineering over the older types of drawtwister with mechanical traverse mechanism. The peak-to-peak distance of the waves along the yarn, due to the 6 ring tilt, is 0.15 inch.

When packages according to the above construction were compared for knittability and stocking performance with packages wound with composite pirn and pirn builds on the same drawtwister, and with the same yarn and the same type and length of tube, it was found:

(a) That the pirn build packages could not'be knitted at all, owing to persistent press-offs when withdrawing yarn from the region of the top traverse reversal, where the moving end got trapped by other yarn layers.

(b) That the number of press-offs for the composite pirn build packages was significantly higher than that for the packages of the invention, and the deviation from the mean leg length of panels knitted from the packages of the invention was much smaller, and the percentage of knitted panels that were outsideil inch of the mean (:tl inch being a tolerance acceptable to the knitter) was minute (at 1%) compared with that of the composite pirn build packages (at 20%).

Similar results were obtained with packages containing 60 ounces of yarn: indeed, in knitting trials carried out, the percentage of panels knitted in which the leg-length was outsideil inch was zero in a high proportion of packages.

The invention will now be described with reference to the accompanying drawings, in which,

FIGURE 1 is a partly perspective, partly diagrammatic sectional view of a drawtwist yarn package according to the invention;

FIGURE 2 is a diagrammatic elevational view of a portion of a drawtwister for winding a yarn package according to the invention;

FIGURE 3 is a graph demonstrating the effect of cone half-angle on take-off tension at various weights of yarn in yarn packages according to the invention.

The yarn package of FIGURE 1 comprises an aluminium tube 1 of 14 /2 inches in length and having a cone angle of 2 on which is wound a build of yarn 3. The traverse as shown diagrammatically in the sectional portion of the drawing, commences at the longest stroke and ends at the shortest; so that the layers of yarn 5 nearest the tube surface are longest and those layers 7 on the outside mid-portion of the build 3 are shortest. The top tapered end-portion -9 of the build is frusto-conical in shape with a cone angle of -23 and the bottom tapered end-portion 11 is likewise so shaped, with a cone angle of 19 /2 FIGURE 2 shows diagrammatically the tilted-ring ring spindle method of winding to produce one form of yarn package according to the invention. Tube 1 is mounted on a rotatable spindle (not shown) within ring 13 which itself is tiltedly-mounted, at an angle of 6 in ring-holder 15. The yarn 7, pasing downwardly through balloon-guide 17, is wound into the build 3 by rotation of the package and by traversing of the ring axially thereof according to a builder motion providing for a gradual diminution in traverse stroke length from the commencement until the completion of winding.

The graph of FIGURE 3 shows how the take-off tension, in milligrams along the ordinate, varies, at the various stages of unwinding a 42-ounce package, shown by the package weight in ounces along the abscissa, depending on the cone angle of the frusto-conical former. The larger tensions occur when withdrawal is from the bottom tapered end-portion of this package build: and it will be seen that towards and at the stage of complete unwinding, i.e. exhaustion, of the packages, the former having a cone angle of /2 leads to usually unacceptably high withdraw-a1 tension from the bottom taper. This finding is reinforced by the results of a knitting evaluation, from which it has been demonstrated that there is a 50%-100% increase in the percentage of knitted parcels having lengths exceedingil inch of the mean, comparing /z with 2 cone angle. The results for a right cylindrical former are, in fact, inferior to those for the /2" frusto-conical former.

We claim:

1. A drawtwist yarn package for use directly in knitting consisting of a continuous monofilamentary yarn of a synthetic polymeric material wound in a build on an aluminimum tube of frusto-conical shape, the cone angle of which is between 1 and 3, said build being composed of coils of yarn in successive layers which decrease in axial length from inside to outside of the build.

2. A yarn package according to claim 1 in which the aluminium tube has a wire-brushed aluminium surface.

3. A yarn package according to claim 1 the coils of which are wavy and in which no substantial number of adjacent coils correspond exactly as to the loci of their paths at any radius of the build.

References Cited UNITED STATES PATENTS 1,522,03 6 1 1925 Snyder 242- 1 18.32 1,839,184 1 2/1931 Kircher 242-1 1 8.32 XR 1,858,410 5/1932 Morey 242118.32 XR 3,064,922 11/1962 Cochran 242- FOREIGN PATENTS 200,972 12/11958 Austria.

552,299 1/ 1923 France. 11,221,167 1/ 1960 France.

800,555 1/ 1958- Great Britain.

901,411 7/ 1962 Great Britain.

238,829 12/ 1945 Switzerland.

STANLEY N. GILREATH, Primary Examiner. 

1. A DRAWTWIST YARN PACKAGE FOR USE DIRECTLY IN KNITTING CONSISTING OF A CONTINUOUS MONOFILAMENTARY YARN OF A SYNTHETIC POLYMERIC MATERIAL WOUND IN A BUILD ON AN ALUMINIUM TUBE OF FRUSTO-CONICAL SHAPE, THE CONE ANGLE OF WHICH IS BETWEEN 1* AND 3*, SAID BUILD BEING COMPOSED OF COILS OF YARN IN SUCCESSIVE LAYERS WHICH DECREASE IN AXIAL LENGTH FROM INSIDE TO OUTSIDE OF THE BUILD. 